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09-09-2009, 01:30 PM
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#1 |
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Gear Jammer
Join Date: May 2007
Location: Myrtle creek OR
Posts: 221
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Tranny choice ?
Hey guys i'm working on a 66 that has the 12 bolt with 4.11s and th400. I use the truck everyday so i found a set of 3.08s to put in. I had a friend give me a 700r4, my question, is it worth wild to swap in the 700r4 or just see how it runs with the 3.08s first?
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09-09-2009, 01:47 PM
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#2 |
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Senior Member
Join Date: Apr 2000
Location: Delta,Pa
Posts: 14,950
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Re: Tranny choice ?
if your going to use the 700r4 keep the 4.11's. if you run both 3.08's and a 700r4 you rpms will be so low in overdrive the truck will lug and actually burn more fuel.it probably wouldnt stay in overdrive very much and would end up searching back and forth from 3rd to od. if it was me i would just run the 3.08's and the th400. the th400 is a ton stronger than the 700r4 and with 3.08's your rpms will be fairly low on the highway.
__________________
Owner of North Point Car Care in Dundalk Md. We specialize in custom exhaust on both modern and classic vehicles. We are a full service auto shop from classics to modern vehicles. Feel free to contact me with questions. I will give a 10% discount to any board member. |
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09-09-2009, 02:32 PM
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#3 |
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1962 C-10
Join Date: Apr 2005
Location: Las Vegas, New Mexico
Posts: 4,978
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Re: Tranny choice ?
I agree. 3.08's are perfect for a 3 speed tranny. If you run a 700r4, it would be best with 3.42's or 3.73's. 4.11's would be fine.
Also, I've heard that 3.08's use a different carrier than 4.11's. I'm sure someone who knows more may chime in about this, but it may be something you want to check into... Anyhow, my vote would be for the 400 with 3.08's...
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Joseph Chavez  "See the USA in a Chevrolet!!" ......................_____ .........________//__{\_____ ,,,,,,,/__(O)___//___/__(O)_/ 1962 C10 Shortbed Fleetside 327/th350 GV overdrive 1974 C10 Longbed Fleetside 350/th350 "The Trash Truck" 1999 Chevy 2500 OBS, Longbed 5.7/4L80E 4x4 2015 GMC Sierra SLE 1500 4x4 |
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09-09-2009, 03:57 PM
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#4 |
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Registered User
Join Date: Feb 2007
Location: Austin, TX
Posts: 3,930
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Re: Tranny choice ?
If you have a stock motor the 700R4 will hold up fine without costing too much. When you start making a bunch of power, that's where a 700R4 starts to get expensive.
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1977 GMC Sierra Grande |
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09-09-2009, 05:37 PM
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#5 |
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Senior Member
Join Date: Apr 2000
Location: Delta,Pa
Posts: 14,950
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Re: Tranny choice ?
as stated above the 4.10 gears use a 4 series carrier and the 3.08 gears use a 3 series carrier. you cant simply just swap gears. you will need a carrier too.
__________________
Owner of North Point Car Care in Dundalk Md. We specialize in custom exhaust on both modern and classic vehicles. We are a full service auto shop from classics to modern vehicles. Feel free to contact me with questions. I will give a 10% discount to any board member. |
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09-10-2009, 07:43 PM
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#6 |
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Gear Jammer
Join Date: May 2007
Location: Myrtle creek OR
Posts: 221
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Re: Tranny choice ?
Thanks for the help guys! I heard about the carrier and the difference in series. So i found a jimmy 12 bolt 70 i think it was and grabbed everything ! Carrier and all. I just want to be able to cruise down the freeway 70 or so and get decent rpm's. I am turning 3500 at 55mph right now and it sucks !
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09-12-2009, 12:09 AM
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#7 |
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Superbad
Join Date: Mar 2007
Location: Pittsburg, CA
Posts: 153
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Re: Tranny choice ?
My 70 ( the one in my avatar ) had 3.08s & I put a 700R4 in it. It ran great on the highway, turned about 1800 RPMs on the highway & got 17 to 18 MPG.
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